Not being particularly good with french it looks as though you are using that setting to compensate for blurring caused by setting a resolution other than a truly supported resolution for your display?

I would set that option back to 100% (rather than the current 120%) and then mess about with your resolution setting until you find the correct one for your monitor (i.e. when the on screen fonts look sharp).

The crude attempt at a "scaling" system in XP never works properly and what you are seeing happens in a lot of programs including parts of Windows itself! As suggested I would switch it back to 100%, set the screen res to whatever works best for you and then if you want to change anything specific use the Advanced button in the Appearance tab of the Display Properties dialogue to tweak individual settings.

I recently tried this in Windows 7 and it too has this problem regardless of the DPI scaling settings.

I tried a util called ResizeEnable that will let you resize fixed windows via a hack. It doesn't quite work but it does let you see the full screen of one of the menu options but it won't let you see the rest of the options at the top.